The matrix metalloproteinase (MMP) stromelysin-3 (ST3) has long been implicated to play an important role in extracellular matrix (ECM) remodeling and cell fate determination during normal and pathological processes. ...The matrix metalloproteinase (MMP) stromelysin-3 (ST3) has long been implicated to play an important role in extracellular matrix (ECM) remodeling and cell fate determination during normal and pathological processes. However like other MMPs, the molecular basis of ST3 function in vivo remains unclear due to the lack of information on its physiological substrates. Furthermore, ST3 has only weak activities toward all tested ECM proteins. Using thyroid hormone-dependent Xenopus laevis metamorphosis as a model, we demonstrated previously that ST3 is important for apoptosis and tissue morphogenesis during intestinal remodeling. Here, we used yeast two-hybrid screen with mRNAs from metamorphosing tadpoles to identify potential substrate of ST3 during development. We thus isolated the 37 kd laminin receptor precursor (LR). We showed that LR binds to ST3 in vitro and can be cleaved by ST3 at two sites distinct from where other MMPs cleave. Through peptide sequencing, we determined that the two cleavage sites are in the extracellular domain between the transmembrane domain and laminin binding sequence. Furthermore, we demon strated that these cleavage sites are conserved in human LR. These results together with high levels of human LR and ST3 expression in carcinomas suggest that LR is a likely in vivo substrate of ST3 and that its cleavage by ST3 may alter cell-extracellular matrix interaction, thus, playing a role in mediating the effects of ST3 on cell fate and behavior ob- served during development and pathogenesis.展开更多
Objective:Unlike other tissues,myocardium has not substitute whick can be used to repair damaged cardiac tissue.This paper proposes engineering 3-D myocardium-like tissue constructs in vitro with bone mesenchymal stem...Objective:Unlike other tissues,myocardium has not substitute whick can be used to repair damaged cardiac tissue.This paper proposes engineering 3-D myocardium-like tissue constructs in vitro with bone mesenchymal stem cells(BMSCs) of infant and poly-lactic-co-glycolic acid(PLGA)in vitro.Methods:Bone marrow was obtained from the sternal marrow cavum outflow of infant with congenital heart disease (CHD)undergoing cardiac operation.BMSCs were obtained by density gradient centrifugation.The cells in passages two were induced in DMED with 10 umol/L 5- Azacytidine(5-Aza)for 24 h.When the induced BMSCS were cultured nearly into filled,the cells were planted in the scaffold of PLGA in 5.5×106 cells/cm2.The cell- scaffold complex has been cultured in the shake cultivation for 1 week,then the complex has been planted in the dorse of the nude mouse.When the experiment had been finished,the histology,immunology,real time PCR and so on were done.Results: The BMSCs of infant with congenital heart disease have the properties of the stable growth and the rapid proliferation.The immunohistochemistry showed that tissue engineered myocardium constructed in vitro expressed some cardiac related proteins such asα-actin,Cx-43,Desmine,cTNI and so on.The transparent myofilaments,gap junctions and intercalated disk-like structure formation could be observed in the 3D tissue-like constructs by transmission electron microscope(TEM).The engineered myocardium-like tissue had the auto-myocardial property as assessed by real time- PCR and so on.Conclusion:The engineered myocardial tissue-like constructs could be built with infant BMSCs and PLGA in vitro.Our results may provide the first step on the long road toward engineering myocardial material for repairing the defect or augmenting the tract in CHD,such as ventricular septal defect,tetralogy of Fallot and so on.展开更多
Salinity is a major soil contamination problem in Australia. To explore salinity remediation, we evaluated the concentrations of sodium （Na）, potassium （K）, magnesium （Mg）, and calcium （Ca） in roots and shoots...Salinity is a major soil contamination problem in Australia. To explore salinity remediation, we evaluated the concentrations of sodium （Na）, potassium （K）, magnesium （Mg）, and calcium （Ca） in roots and shoots and in the supporting soil of the naturally occurring grasses, Cynodon dactylon and Thinopyrurn ponticum, at two salt-affected sites, Gumble and Cundumbul in central-western New South Wales, Australia. The physiological parameters of the two grass species, including net photosynthetic rate （Pn）, stomatal conductance （gs）, and intercellular CO2 concentration （Ci）, were investigated using one mature leaf from C. dactylon and T. ponticum populations. Increasing salinity levels in the topsoil had a significant influence on Ci and gs, whereas no significant effect occurred on Pn in C. dactylon and T. ponticum. The Pn values in C. dactylon and T. ponticum were greater at Cundumbul than at Gumble. The greater Mg concentration facilitated greater Pn in C. dactylon and T. ponticum populations at Cundumbul than Gumble. With increasing salinity levels in the soil, Na accumulation increased in C. dactylon and T. ponticum. The ratio between K and Na was ~ 1 in roots and shoots of both populations irrespective of the sites. Bioaccumulation factor （BF） and translocation factor （TF） results revealed that K and Na translocations were significantly higher in T. ponticum than in C. dactylon, whereas Ca and Mg translocations were significantly higher in C. dactylon than in T. ponticum. Accumulation of Na, K, Mg, and Ca ions was higher in T. ponticum than in C. dactylon; therefore, we suggest that T. ponticum as a greater salt accumulator than C. dactylon could be used for revegetation and phytoremediation of the salt-affected soils.展开更多
文摘The matrix metalloproteinase (MMP) stromelysin-3 (ST3) has long been implicated to play an important role in extracellular matrix (ECM) remodeling and cell fate determination during normal and pathological processes. However like other MMPs, the molecular basis of ST3 function in vivo remains unclear due to the lack of information on its physiological substrates. Furthermore, ST3 has only weak activities toward all tested ECM proteins. Using thyroid hormone-dependent Xenopus laevis metamorphosis as a model, we demonstrated previously that ST3 is important for apoptosis and tissue morphogenesis during intestinal remodeling. Here, we used yeast two-hybrid screen with mRNAs from metamorphosing tadpoles to identify potential substrate of ST3 during development. We thus isolated the 37 kd laminin receptor precursor (LR). We showed that LR binds to ST3 in vitro and can be cleaved by ST3 at two sites distinct from where other MMPs cleave. Through peptide sequencing, we determined that the two cleavage sites are in the extracellular domain between the transmembrane domain and laminin binding sequence. Furthermore, we demon strated that these cleavage sites are conserved in human LR. These results together with high levels of human LR and ST3 expression in carcinomas suggest that LR is a likely in vivo substrate of ST3 and that its cleavage by ST3 may alter cell-extracellular matrix interaction, thus, playing a role in mediating the effects of ST3 on cell fate and behavior ob- served during development and pathogenesis.
基金The Tackle Key Problems in Science and Technology, Shanxi Province grant number: 20080311061-2
文摘Objective:Unlike other tissues,myocardium has not substitute whick can be used to repair damaged cardiac tissue.This paper proposes engineering 3-D myocardium-like tissue constructs in vitro with bone mesenchymal stem cells(BMSCs) of infant and poly-lactic-co-glycolic acid(PLGA)in vitro.Methods:Bone marrow was obtained from the sternal marrow cavum outflow of infant with congenital heart disease (CHD)undergoing cardiac operation.BMSCs were obtained by density gradient centrifugation.The cells in passages two were induced in DMED with 10 umol/L 5- Azacytidine(5-Aza)for 24 h.When the induced BMSCS were cultured nearly into filled,the cells were planted in the scaffold of PLGA in 5.5×106 cells/cm2.The cell- scaffold complex has been cultured in the shake cultivation for 1 week,then the complex has been planted in the dorse of the nude mouse.When the experiment had been finished,the histology,immunology,real time PCR and so on were done.Results: The BMSCs of infant with congenital heart disease have the properties of the stable growth and the rapid proliferation.The immunohistochemistry showed that tissue engineered myocardium constructed in vitro expressed some cardiac related proteins such asα-actin,Cx-43,Desmine,cTNI and so on.The transparent myofilaments,gap junctions and intercalated disk-like structure formation could be observed in the 3D tissue-like constructs by transmission electron microscope(TEM).The engineered myocardium-like tissue had the auto-myocardial property as assessed by real time- PCR and so on.Conclusion:The engineered myocardial tissue-like constructs could be built with infant BMSCs and PLGA in vitro.Our results may provide the first step on the long road toward engineering myocardial material for repairing the defect or augmenting the tract in CHD,such as ventricular septal defect,tetralogy of Fallot and so on.
文摘Salinity is a major soil contamination problem in Australia. To explore salinity remediation, we evaluated the concentrations of sodium （Na）, potassium （K）, magnesium （Mg）, and calcium （Ca） in roots and shoots and in the supporting soil of the naturally occurring grasses, Cynodon dactylon and Thinopyrurn ponticum, at two salt-affected sites, Gumble and Cundumbul in central-western New South Wales, Australia. The physiological parameters of the two grass species, including net photosynthetic rate （Pn）, stomatal conductance （gs）, and intercellular CO2 concentration （Ci）, were investigated using one mature leaf from C. dactylon and T. ponticum populations. Increasing salinity levels in the topsoil had a significant influence on Ci and gs, whereas no significant effect occurred on Pn in C. dactylon and T. ponticum. The Pn values in C. dactylon and T. ponticum were greater at Cundumbul than at Gumble. The greater Mg concentration facilitated greater Pn in C. dactylon and T. ponticum populations at Cundumbul than Gumble. With increasing salinity levels in the soil, Na accumulation increased in C. dactylon and T. ponticum. The ratio between K and Na was ~ 1 in roots and shoots of both populations irrespective of the sites. Bioaccumulation factor （BF） and translocation factor （TF） results revealed that K and Na translocations were significantly higher in T. ponticum than in C. dactylon, whereas Ca and Mg translocations were significantly higher in C. dactylon than in T. ponticum. Accumulation of Na, K, Mg, and Ca ions was higher in T. ponticum than in C. dactylon; therefore, we suggest that T. ponticum as a greater salt accumulator than C. dactylon could be used for revegetation and phytoremediation of the salt-affected soils.
